The multiple caretaker paradox: Data from Holland and Israel

FSW - Gezinsopvoeding - Ou

Pre-mRNA splicing in higher plants.

P re-mRNA splicing is one of the fundamental processes in constitutive and regulated gene expression in eukaryotes. During splicing, introns present in primary gene transcripts are removed and exons are ligated to produce translationally competent mRNAs. The basic mechanism of intron excision is similar in all eukaryotes. The reaction is mediated by the spliceosome, a large ribonucleoprotein (RNP) complex, which is assembled anew at each intron from small nuclear RNP particles (U-snRNPs) and numerous protein factors. Spliceosome assembly is a highly ordered and dynamic reaction, involving hydrolysis of several ATP molecules and many structural rearrangements Properties of plant introns The intron and exon organization of higher plant genes is similar to that of vertebrates In spite of these similarities, the requirements for intron recognition in plants differ from those in other eukaryotes, and plant cells generally fail to splice heterologous pre-mRNAs. The most important difference is a strong compositional bias for UA-or U-rich sequences in plant introns compared with those from yeast and vertebrates U12-type introns A minor class of nuclear pre-mRNA introns, referred to as U12-type or AT-AC introns (because they frequently start with AT and terminate with AC) have recently been described 3,13 . These introns contain different splice site and branch point sequences, and are excised by an alternative U12-type spliceosom

Parental attachment and childrens socio-emotional development: Some findings on the validity of the adult attachment interview in the Netherlands

FSW - Gezinsopvoeding - Ou

Post-transcriptional Regulation of Gene Expression in Plants during Abiotic Stress

Land plants are anchored in one place for most of their life cycle and therefore must constantly adapt their growth and metabolism to abiotic stresses such as light intensity, temperature and the availability of water and essential minerals. Thus, plants’ subsistence depends on their ability to regulate rapidly gene expression in order to adapt their physiology to their environment. Recent studies indicate that post-transcriptional regulations of gene expression play an important role in how plants respond to abiotic stresses. We will review the different mechanisms of post-transcriptional regulation of nuclear genes expression including messenger RNA (mRNA) processing, stability, localization and protein translation, and discuss their relative importance for plant adaptation to abiotic stress

Evolutionary conservation and regulation of particular alternative splicing events in plant SR proteins

Alternative splicing is an important mechanism for fine tuning of gene expression at the post-transcriptional level. SR proteins govern splice site selection and spliceosome assembly. The Arabidopsis genome encodes 19 SR proteins, several of which have no orthologues in metazoan. Three of the plant specific subfamilies are characterized by the presence of a relatively long alternatively spliced intron located in their first RNA recognition motif, which potentially results in an extremely truncated protein. In atRSZ33, a member of the RS2Z subfamily, this alternative splicing event was shown to be autoregulated. Here we show that atRSp31, a member of the RS subfamily, does not autoregulate alternative splicing of its similarily positioned intron. Interestingly, this alternative splicing event is regulated by atRSZ33. We demonstrate that the positions of these long introns and their capability for alternative splicing are conserved from green algae to flowering plants. Moreover, in particular alternative splicing events the splicing signals are embedded into highly conserved sequences. In different taxa, these conserved sequences occur in at least one gene within a subfamily. The evolutionary preservation of alternative splice forms together with highly conserved intron features argues for additional functions hidden in the genes of these plant-specific SR proteins

Expert consensus recommendations on the cardiogenetic care for patients with thoracic aortic disease and their first-degree

Background: Thoracic aortic aneurysm (TAA) is a potentially life-threatening disorder with a strong genetic component. The number of genes implicated in TAA has increased exponentially over the last decade. Approximately 20% of patients with TAA have a positive family history. As most TAA remain asymptomatic for a long time, screening of at risk relatives is warranted to prevent complications. Existing international guidelines lack detailed instructions regarding genetic evaluation and family screening of TAA patients. We aimed to develop a consensus document to provide medical guidance for all health care professionals involved in the recognition, diagnosis and treatment of patients with thoracic aortic disease and their relatives. Methods: A multidisciplinary panel of experts including cardiologists, cardiothoracic surgeons, clinical geneticists and general practitioners, convened to review and discuss the current literature, guidelines and clinical practice on genetic testing and family screening in TAA. Results: There is a lack of high-quality evidence in the literature. This consensus statement, based on the available literature and expert opinions, summarizes our recommendations in order to standardize and optimize the cardiogenetic care for patients and families with thoracic aortic disease. In particular, we provide criteria to identify those patients most likely to have a genetic predisposition, and discuss the preferred modality and frequency of screening in their relatives. Conclusions: Age, family history, aortic size and syndromic features determine who is advised to have genetic testing as well as screening of first-degree relatives. There is a need for more prospective multicenter studies to optimize current recommendations

Role of Cajal Bodies and Nucleolus in the Maturation of the U1 snRNP in Arabidopsis

Background: The biogenesis of spliceosomal snRNPs takes place in both the cytoplasm where Sm core proteins are added and snRNAs are modified at the 59 and 39 termini and in the nucleus where snRNP-specific proteins associate. U1 snRNP consists of U1 snRNA, seven Sm proteins and three snRNP-specific proteins, U1-70K, U1A, and U1C. It has been shown previously that after import to the nucleus U2 and U4/U6 snRNP-specific proteins first appear in Cajal bodies (CB) and then in splicing speckles. In addition, in cells grown under normal conditions U2, U4, U5, and U6 snRNAs/snRNPs are abundant in CBs. Therefore, it has been proposed that the final assembly of these spliceosomal snRNPs takes place in this nuclear compartment. In contrast, U1 snRNA in both animal and plant cells has rarely been found in this nuclear compartment. Methodology/Principal Findings: Here, we analysed the subnuclear distribution of Arabidopsis U1 snRNP-specific proteins fused to GFP or mRFP in transiently transformed Arabidopsis protoplasts. Irrespective of the tag used, U1-70K was exclusively found in the nucleus, whereas U1A and U1C were equally distributed between the nucleus and the cytoplasm. In the nucleus all three proteins localised to CBs and nucleoli although to different extent. Interestingly, we also found that the appearance of the three proteins in nuclear speckles differ significantly. U1-70K was mostly found in speckles whereas U1A and U1C in,90 % of cells showed diffuse nucleoplasmic in combination with CBs and nucleolar localisation. Conclusions/Significance: Our data indicate that CBs and nucleolus are involved in the maturation of U1 snRNP. Difference

Role of Cajal Bodies and Nucleolus in the Maturation of the U1 snRNP in Arabidopsis

Background: The biogenesis of spliceosomal snRNPs takes place in both the cytoplasm where Sm core proteins are added and snRNAs are modified at the 59 and 39 termini and in the nucleus where snRNP-specific proteins associate. U1 snRNP consists of U1 snRNA, seven Sm proteins and three snRNP-specific proteins, U1-70K, U1A, and U1C. It has been shown previously that after import to the nucleus U2 and U4/U6 snRNP-specific proteins first appear in Cajal bodies (CB) and then in splicing speckles. In addition, in cells grown under normal conditions U2, U4, U5, and U6 snRNAs/snRNPs are abundant in CBs. Therefore, it has been proposed that the final assembly of these spliceosomal snRNPs takes place in this nuclear compartment. In contrast, U1 snRNA in both animal and plant cells has rarely been found in this nuclear compartment. Methodology/Principal Findings: Here, we analysed the subnuclear distribution of Arabidopsis U1 snRNP-specific proteins fused to GFP or mRFP in transiently transformed Arabidopsis protoplasts. Irrespective of the tag used, U1-70K was exclusively found in the nucleus, whereas U1A and U1C were equally distributed between the nucleus and the cytoplasm. In the nucleus all three proteins localised to CBs and nucleoli although to different extent. Interestingly, we also found that the appearance of the three proteins in nuclear speckles differ significantly. U1-70K was mostly found in speckles whereas U1A and U1C in,90 % of cells showed diffuse nucleoplasmic in combination with CBs and nucleolar localisation. Conclusions/Significance: Our data indicate that CBs and nucleolus are involved in the maturation of U1 snRNP. Difference